1. Field of the Invention
The present invention relates to a measuring apparatus capable of measuring a wind pressure, and more particularly, to a bidirectional wind pressure detecting apparatus including wind pressure sensors installed at introduction and discharge ports, through which air is introduced and discharged, to measure a wind pressure even when a direction of the wind is reversed.
2. Discussion of Related Art
In general, as is well known in the art, a freezing and refrigerating apparatus includes a compressor configured to compress a refrigerant, a condensing heat exchanger and a condensing fan configured to condense a high temperature and high pressure refrigerant compressed by the compressor into a liquid refrigerant state, an expansion valve configured to expand the liquid refrigerant condensed from the condensing heat exchanger and change the refrigerant into a two-phase state of a liquid phase and a gas phase, and an evaporation heat exchanger and an evaporation fan configured to evaporate the two-phase refrigerant expanded through the expansion valve.
Here, since an exchange operation in the evaporation heat exchanger absorbs heat from the suctioned air, a temperature difference occurs between the inside and the outside of the evaporation heat exchanger.
When the temperature difference between the inside and the outside of a forced circulation evaporation heat exchanger 6 is above a certain level, frost formation, in which an outer wall of the evaporation heat exchanger is covered with frost, occurs.
Since such a frost layer acts not only as a heat resistor configured to prevent heat transfer between air and a refrigerant but also to increase a system resistance of the air by blocking a flow path of the air passing through the evaporation heat exchanger, an air volume introduced into the evaporation heat exchanger 6 is reduced to decrease an air-side heat transfer coefficient of the evaporation heat exchanger and to cause a reduction in heat transfer of the evaporation heat exchanger.
A defrosting operation may be performed to flow the refrigerant in an opposite direction of a normal operation, or a separate electric heater installed around the evaporation heat exchanger covered with frost may be operated to prevent generation of such a problem.
In the related art, a wind pressure detecting apparatus 20 shown in FIGS. 1 to 4 is used to detect such a defrosting start point.
FIG. 1 is a schematic side view showing the conventional wind pressure detecting apparatus 20 installed at an evaporation heat exchanger 11 of a freezing and refrigerating apparatus and a freezing apparatus. The wind pressure detecting apparatus 20 is installed at a forced circulation evaporation heat exchanger 11 provided with a fan 12.
Here, the defrosting start point is detected by the wind pressure detecting apparatus 20.
The wind pressure detecting apparatus 20 is installed at the evaporation heat exchanger 11 of the freezing and refrigerating apparatus and the freezing apparatus to detect a variation in wind pressure caused by the fan 12, performing a function of activating a defrosting operation.
As shown in FIGS. 2 and 3, the wind pressure detecting apparatus 20 includes a housing 21, a wind pressure sensor 22 and an operation plate 23.
That is, when frost formation of the forced circulation evaporation heat exchanger 11 applies a load to the fan 12 and air flow in the forced circulation evaporation heat exchanger 11 is reduced, external air is introduced into the forced circulation evaporation heat exchanger 11, and at this time, the wind pressure sensor 22 is operated by the operation plate 23.
The operation plate 23 is installed in the housing 21 and connected to the wind pressure sensor 22. When external air is introduced into the housing 21, the operation plate 23 is pushed toward the wind pressure sensor 22 by the air flow to operate the wind pressure sensor 22.
Since the conventional wind pressure detecting apparatus is disclosed in detail in Korean Patent No. 674180, overlapping description will be omitted.
However, the conventional wind pressure detecting apparatus 20 can be operated only when the air introduced from the outside is in one direction.
That is, as shown in FIG. 1, only when the air is introduced from a right side to a left side of the drawing, is the operation plate 23 operated to activate the wind pressure sensor 22.
However, as shown in FIG. 1, while the air flows from the right side to the left side of the operation plate 23 in the case of the forced circulation evaporation heat exchanger 11, the air may flow in a reversed direction according to embodiments.
That is, as shown in FIG. 4, when the forced circulation evaporation heat exchanger 11 is installed in the reversed direction, the air flows in the opposite direction of the direction that can be measured by the conventional wind pressure detecting apparatus 20, and thus the wind pressure cannot be measured.
Accordingly, since the conventional wind pressure detecting apparatus 20 cannot detect a wind pressure when the forced circulation evaporation heat exchanger 11 is installed in the reversed direction, an additional wind pressure detecting apparatus 20 must be installed to detect a wind pressure of the air flow in the reversed direction.
In addition, since the conventional wind pressure detecting apparatus 20 includes a heater disposed at the outside thereof, the temperature in the wind pressure detecting apparatus 20 cannot be easily controlled.